Plenty of it. Going trough the transform hierarchy (tons of 4x4 matrix multiplications which definitely are vectorized) and then the physics simulations, and that’s just part of it.

Couldn't be further from the truth. Rasterization is all linear algebra. That being said, you don't really see games with the likes of AVX-512.

That all happens on the GPU. There's a tiny (trivial) amount of linalg on the CPU and the rest is punted to shaders.

Physics are still often CPU, though I guess sometimes on compute shaders by now?

Then there's bad engines, e.g. Fallout 4 seems like it might be calculating some part of the shadows on the CPU…

It's not always trivial, especially if any computational geometry is being done (read: any game with a landscape).

Floating point yes, but SIMD depends.